Expanding the operating region of a field effect transistor made of e.g. GaAs facilitates increasing the output power of an inverter circuit, switching circuit, microwave circuit and the like. The GaAs-based material has low thermal conductivity. Thus, for instance, cells are arranged on a narrow and thin chip, thereby improving heat dissipation.
Wide bandgap semiconductors such as SiC and GaN have high thermal conductivity. Thus, it is easy to increase the output power by increasing the heat generation density several times higher than that of GaAs without thinning the thickness of the chip. In this case, the thermal resistance can be reduced by optimizing the spacing between a plurality of cell regions, i.e., partitioned operating regions.
In the case of microwave frequency high-power amplifier circuits based on e.g. HEMT, it is desired to arrange a plurality of cell regions so as to avoid loop oscillation.